Commonly referred to as the Martin-Bell syndrome or the Marker X syndrome, Fragile X is the most common form of inherited mental handicap in boys and a significant cause in girls. The inheritance is different from common dominant or recessive inheritance patterns.
A fragile area on the X chromosome tends to repeat bits of the genetic code. The more repeats, the more likely there is to be a problem. Boys and girls can both be affected, but because boys have only one X chromosome, a single fragile X is more likely to affect them.
Signs of Fragile X Syndrome:
- Family history of fragile X syndrome or mental handicap
- Mental handicap
- Large testicles
- Tendency to avoid eye contact
- Hyperactive behavior
- Large forehead and/or ears with a prominent jaw